Enable remote execution

Author: dtolnay

platforms/defs.bzl

@@ -1,3 +1,5 @@
+load("//remote_execution:config.bzl", "executor_config")
+
 def _platform_impl(ctx: AnalysisContext) -> list[Provider]:
     platform_label = ctx.label.raw_target()
     constraints = {}
@@ -10,11 +12,6 @@ def _platform_impl(ctx: AnalysisContext) -> list[Provider]:
         for label, value in dep[ConfigurationInfo].constraints.items():
             constraints[label] = value
 
-    use_windows_path_separators = False
-    for value in constraints.values():
-        if str(value.label) == "prelude//os/constraints:windows":
-            use_windows_path_separators = True
-
     configuration = ConfigurationInfo(
         constraints = constraints,
         values = {},
@@ -49,11 +46,7 @@ def _platform_impl(ctx: AnalysisContext) -> list[Provider]:
         [ExecutionPlatformInfo(
             label = platform_label,
             configuration = configuration,
-            executor_config = CommandExecutorConfig(
-                local_enabled = True,
-                remote_enabled = False,
-                use_windows_path_separators = use_windows_path_separators,
-            ),
+            executor_config = executor_config(configuration),
         )] if ctx.attrs.execution_platform else []
     )
 

remote_execution/Dockerfile

@@ -0,0 +1,12 @@
+FROM debian:trixie-slim
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    clang-19 \
+    lld-19 \
+    python3 \
+    xz-utils \
+    zlib1g-dev \
+    && rm -rf /var/lib/apt/lists/* \
+    && ln -s clang-19 /usr/bin/clang \
+    && ln -s clang++-19 /usr/bin/clang++ \
+    && ln -s lld-19 /usr/bin/lld

remote_execution/README.md

@@ -0,0 +1,11 @@
+To enable Remote Execution, add the following 4 entries to `.buckconfig.local`
+in the repo root, using values given by your Remote Execution provider. For
+example BuildBuddy would look like this (but with a real API key):
+
+```ini
+[buck2_re_client]
+engine_address = remote.buildbuddy.io
+action_cache_address = remote.buildbuddy.io
+cas_address = remote.buildbuddy.io
+http_headers = x-buildbuddy-api-key:zzzzzzzzzzzzzzzzzzzz
+```

remote_execution/config.bzl

@@ -0,0 +1,25 @@
+def executor_config(configuration: ConfigurationInfo) -> CommandExecutorConfig:
+    use_windows_path_separators = False
+    for value in configuration.constraints.values():
+        if str(value.label) == "prelude//os/constraints:windows":
+            use_windows_path_separators = True
+
+    if read_config("buck2_re_client", "engine_address"):
+        return CommandExecutorConfig(
+            local_enabled = True,
+            remote_enabled = True,
+            use_limited_hybrid = True,
+            remote_execution_properties = {
+                "OSFamily": "Linux",
+                "dockerNetwork": "off",
+                "container-image": "docker://docker.io/dtolnay/buck2-rustc-bootstrap:latest",
+            },
+            remote_execution_use_case = "buck2-rustc-bootstrap",
+            use_windows_path_separators = use_windows_path_separators,
+        )
+    else:
+        return CommandExecutorConfig(
+            local_enabled = True,
+            remote_enabled = False,
+            use_windows_path_separators = use_windows_path_separators,
+        )